45 CFR §1176.2

1. (a)Part-time employment means employment of 16 to 32 hours a week under a schedule consisting of an equal or varied number of hours per day, whether in a position which would be part-time without regard to the Act or one established to allow job-sharing or comparable arrangements, but does not include employment on a temporary or intermittent basis.
2. (b)Career employment includes competitive and excepted service employees in tenure groups I and II.